1. Field of the Invention
The present invention relates to a method of generating object-oriented multimedia data and a method of reconstructing the same, and more particularly, to a method of generating object-oriented multimedia data so that some of a plurality of objects constituting the multimedia data can be changed to have a user's desired attributes, and a method of reconstructing the same.
2. Description of the Related Art
Recently, advent of various digital broadcasting environments, such as digital multimedia broadcasting (DMB), has resulted in development of application service models that provide various data services. An object-oriented multimedia system is capable of processing media items of video in units of objects and is thus very available for providing interactive services. In the fields of mobile broadcasting or communications, techniques of providing data services using an MPEG-4 Binary Format of Scene (BIFS) have been introduced.
An MPEG-4 system composes a scene with various video/audio media objects by using a scene descriptor, and enables the media objects to be processed in units of objects. MPEG-4 BIFS which is a standard MPEG-4 technique of scene description is used in determining the temporal/spatial arrangement of audio or video objects, and is transmitted together with the result of encoding the video or audio objects.
FIG. 1 is a diagram illustrating a related art method of composing a multimedia scene 120 by using a scene tree.
Referring to FIG. 1, a scene tree 102 is a hierarchical structure in which nodes allocated to objects that constitute one multimedia scene are linked to one another. A scene descriptor stream 104 contains information regarding the scene tree 102 and the nodes of the scene tree 102, and an object descriptor stream 106 contains information regarding the respective objects. A first media source 112 represents a moving picture, a second media source 114 and a third media source 116 represent still images, and a fourth media source 118 represents sound.
The multimedia scene 120 is composed by arranging the media sources 112 through 118 in temporal and spatial locations that have been defined in an encoding process based on the information in the scene descriptor stream 104 and the object descriptor stream 106, and then executing a predetermined event.
FIG. 2 is a diagram illustrating a related art method of changing an object. Referring to FIG. 2, a first scene 120 is a multimedia scene constructed using objects being initially set during an encoding process. According to the related art method, a transmitting side instructs that a BIFS be changed in order to change each of multimedia objects. For example, the transmitting side deletes a node allocated to the first media source 112 of FIG. 1 from a first scene tree 202 in order to change the first media source 112. Then the scene tree 202 is changed to a second scene tree 212 since the node designating the first media source 112 is deleted. Thereafter the transmitting side inserts a new node containing desired media information into the scene tree 212 thus generating a third scene tree 222. A second scene 220 shows the result of executing a media source changed with the third scene tree 222 into which the new node has been inserted.
However, it is difficult to maximize the advantages of interactive multimedia when using the related art method in which the transmitting side individually gives commands in order to change information regarding each object of the multimedia. Also, the related art method is inefficient in terms of reproducing a large amount of multimedia contents while processing an event in real time.